A conventional railcar transmits an output of a diesel engine through a torque converter to a wheel to directly drive the wheel. Therefore, there are problems of low fuel efficiency, high noise level, and the like at the time of starting and accelerating. A storage battery car that uses electric power from a storage battery does not have the problems described above for the railcar. However, the storage battery car is more expensive than the railcar and needs to be charged frequently, and therefore is not suitable for a long-distance operation.
Patent Literature 1 mentioned below discloses a diesel hybrid vehicle in which a diesel engine drives a power generator, and electric power from the power generator and electric power from a storage battery serve as a power supply.